Agent-based Modeling of Rural-urban Migration in China We propose to develop a large-scale agent-based model of rural-to-urban migration in China. Large-scale migrations, both within countries and across countries, are transforming the world's population. Agent-based modeling (ABM) is a promising and underutilized means for understanding the implications of these complex migrations for population distribution and growth because it can include feedback loops, allow actor-place interactions, and reveal unexpected, emergent properties of the complex system of migration. Recent developments in ABM, notably algorithms for the efficient use of powerful computing clusters to estimate models with billions of actors (Parker and Epstein 2011), make this technique especially promising for modeling large, complex spatial processes. Thus, we would argue that the development of ABM to study large-scale migrations is an innovation that is of high scientific priority for population research. China is an excellent choice for the development of the first such model because it has, since the mid-1980s, undergone the largest single migration in the world's history, transferring some 230 million rural people by 2011, accounting for 17.4% of China's total population (Chinese National Bureau of Statistics 2012). About half of China's rural migration is from the rural inner provinces to the urbanized coast. Rural migrants are drawn to coastal areas primarily because of the high employment prospects in export-oriented industries and migrant networks (Hao et al. 2013). This monumental population shift has global economic, demographic, health, and political ramifications. While its importance is well documented, little has been done to identify and test the basic underlying causal mechanisms. The scale and duration of China's mass migration present a unique opportunity to gain valuable insights into this important historical phenomenon. The project will (1) explore, develop, and validate the conceptual model by reformulating and improving existing theories to apply to China's rural-urban migration; (2) develop a large-scale agent-based model of rural-urban migration in China, using empirically calibrated initial conditions, ex ante structural parameters, and open parameters to be experimented ex post, and validate the simulated stylized patterns against the reality; (3) test the explanatory power of each of the component theories integrated in our base-case model; (4) explore the dynamic outcomes of the base-case model under varying policies, economic conditions, individual preferences, and initial population conditions, and (5) find general principles of mass migration and to produce and publish our methods and results so that ABM can be applied to other large, complex migration flows.